Immigration.

My favorite question for americans is "where are you from?"
Generally I get the state, along with all the places they've moved, rolling down a highway or two. Then I get the family history of how such and such great-grandparents/grandparents/parents from such and such country came here. And the most amazing thing is that Americans can usually to the exact ratio tell you what generation american they are. But I wonder about the politicians. Are they the only americans without a family tree?